Venus Williams got the better of her sister Serena Williams on the first leg of their African exhibition tour.

Venus, diagnosed last year with an autoimmune disease, claimed a 6-4 7-5 victory in Nigeria on Friday.

"For me to get a win against Serena, it means 2013 is going to be a great year," Venus said.

Serena, who ends the year as world No. 3 after a superb second half of the season, winning Wimbledon and the US Open, as well as Olympic gold and the season-ending WTA Championships, struggled with her clay court game at the Lagos Lawn Tennis Centre.

"We've worked so hard this year; Venus has worked so hard," Serena said. "We hope to keep this momentum going into next year."

The pair are due to meet again at Johannesburg's Ellis Park Indoor Arena in South Africa on Sunday.